Real Solar Power May be a Decade Away

It may take at least 10 or more years of intensive research and development to reduce the cost of solar energy to levels competitive with petroleum, according to an authority on the topic.

"Solar can potentially provide all the electricity and fuel we need to power the planet," said Harry Gray, Ph.D. Gray was scheduled to at the 235th American Chemical Society meeting.

Gray is the Arnold O. Beckman Professor of Chemistry and Founding Director of the Beckman Institute at the California Institute of Technology. He is the principal investigator in a National Science Founation-funded Phase I Chemical Bonding Center – a Caltech/MIT collaboration – and a principal investigator at the Caltech Center for Sustainable Energy Research (CCSER).

"The Holy Grail of solar research is to use sunlight efficiently and directly to 'split' water into its elemental constituents – hydrogen and oxygen – and then use the hydrogen as a clean fuel," Gray said.

This research has the goal of transforming the industrialized world from one powered by fossil fuels to one powered by sunlight. The CBC research focuses on converting sunlight to chemical fuels while research in the CCSER focuses on generating electricity from sunlight and developing fuel cells.

Gray cited the vast potential of solar energy, noting that more energy from sunlight strikes the Earth in one hour than all of the energy consumed on the planet in one year.

The single biggest challenge, Gray said, is reducing costs so that a large-scale shift away from coal, natural gas, and other non-renewable sources of electricity makes economic sense. Gray estimated the average cost of photovoltaic energy at 35 to 50 cents per kilowatt-hour. By comparison, other sources are considerably less expensive, with coal and natural gas hovering around 5 to 6 cents per kilowatt-hour.

Because of its other advantages – being clean and renewable, for instance – solar energy need not match the cost of conventional energy sources, Gray indicated. The breakthrough for solar energy probably will come when scientists reduce the costs of photovoltaic energy to about 10 cents per kilowatt-hour, he added. "Once it reaches that level, large numbers of consumers will start to buy in, driving the per-kilowatt price down even further. I believe we are at least 10 years away from photovoltaics being competitive with more traditional forms of energy."

Major challenges include developing cheap solar cells that work without deterioration and reducing the amounts of toxic materials used in the manufacture of these cells. But producing low-cost photovoltaics is only a step in the right direction. Chemists also need to focus on the generation of clean fuels at costs that can compete with oil and coal.

Gray emphasized this point: "The pressure is on chemists to make hydrogen from something other than natural gas or coal. We’ve got to start making it from sunlight and water."

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